System and method for the dynamic presentation of the contents of a plurality of documents for rapid skimming

ABSTRACT

A method and system for the dynamic presentation of the contents of a plurality of documents on a display is disclosed. The method and system comprises receiving a plurality of documents and providing a plurality of topically rich capsule overviews corresponding to the plurality of documents. The method and system also includes dynamically delivering document content encapsulated in the plurality of capsule overviews.  
     In so doing, a system and method in accordance with the present invention can present thematic capsule overviews of the documents to users. A capsule overview is derived for the entire document, which will depict the core content of an average length article in a more accurate and representative manner than utilizing conventional techniques. The capsule overviews, delivered in a variety of dynamic presentation modes, allow the user to quickly get a sense of what a document is about, and decide whether they want to read it in more detail. If so, the system and method greatly facilitate the process of focused navigation into the parts of the document which may be of particular interest to the user.  
     In a preferred embodiment, the capsule overviews include a containment hierarchy which relates the different information levels in a document together, and which includes a collection of highly salient topic stamps embedded in layers of progressively richer and more informative contextualized text fragments.  
     The novel presentation metaphors which the invention utilizes are based on notions of temporal typography, in particular for exploiting the interactions between form and content.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is related to co-pending patentapplication Ser. No. (JAS786P), entitled “A System and Method forCharacterizing Content of Text Documents,” filed on the same day andassigned to the same Assignee as the present application.

FIELD OF THE INVENTION

[0002] The present invention relates generally to a system and methodfor reviewing documents. More particularly, the present inventionrelates to presentation of documents in a manner that allows the user toquickly ascertain their contents.

BACKGROUND OF THE INVENTION

[0003] Documents obtained via an electronic medium (i.e., the Internetor on-line services, such as AOL, Compuserve or other services) areoften provided in such volume that it is important to be able tosummarize them. Oftentimes, it is desired to be able to quickly obtain abrief (i.e., a few sentences or a paragraph length) summary of thedocument rather than reading it in its completeness. Most typically,such documents span several paragraphs to several pages in length. Thepresent invention concerns itself with this kind of document,hereinafter referred to as average length document.

[0004] Present day summarization technologies fall short of deliveringfully informative summaries of documents. To some extent, this is sobecause of shortcomings of the state-of-the-art in natural languageprocessing; in general, the issue of how to customize a summarizationprocedure for a specific information seeking task is still an open one.However, given the rapidly growing volume of document-based informationon-line, the need for any kind of document abstraction mechanism is sogreat that summarization technologies are beginning to get deployed inreal world situations.

[0005] The majority of techniques for “summarization”, as applied toaverage-length documents, fall within two broad categories. A class oftechniques mine a document for certain pre-specified pieces ofinformation, typically defined apriori, on the basis of fixing the mostcharacteristic features of a known domain of interest. Other approachesrely, in effect, on ‘re-using’ certain fragments of the original text;these have been identified, typically by some similarity metric, asclosest in meaning to the whole document. This categorization is not arigid one: a number of approaches (as exhibited, for instance, in arecent workshop on Association for Computational Linguistics,“Proceedings of a Workshop on Intelligent, Scalable, TextSummarization,” Madrid, Spain, 1997) use strong notions of topicality(B. Boguraev and C. Kennedy, “Salience-based content characterization oftext documents,” in Proceedings of ACL '97 Workshop on Intelligent,Scalable Text Summarization, Madrid, Spain, 1997), (E. Hovy and C. Y.Lin, “Automated text summarization in SUMMARIST,” in Proceedings of ACL'97 Workshop on Intelligent, Scalable Text Summarization, Madrid, Spain,1997), lexical chains (R. Barzilay and M. Elhadad, “Using lexical chainsfor text summarization,” in Proceedings of ACL '97 Workshop onIntelligent, Scalable Text Summarization, Madrid, Spain, 1997), anddiscourse structure (D. Marcu, “From discourse structures to textsummaries”, in Proceedings of ACL '97 Workshop on Intelligent, ScalableText Summarization, Madrid, Spain, 1997), (U. Hahn and M. Strube,“Centered segmentation: scaling up the centering model to globaldiscourse structure,” in Proceedings of ACL-EACL/97, 35th Annual Meetingof the Association for Computational Linguistics and 8th Conference ofthe European Chapter of the Association for Computational Linguistics,Madrid, Spain, 1997), thus laying claim to newer sets of methods.

[0006] Still, at a certain level of abstraction, all approaches share afundamental similarity: summarization methods today rely, in essence, onsubstantial data reduction over the original document source. Such aposition leads to several usability questions.

[0007] Given the extracted fragments which any particular method hasidentified as worth preserving, what is an optimal way of encapsulatingthese into a coherent whole, for presenting to the user? Acknowledgingthat different information management tasks may require different kindsof summary, even from the same document, how should the data discardedby the reduction process be retained, in case a reference is necessaryto a part of the document not originally included in the summary? Whatare the trade-offs in fixing the granularity of analysis: for instance,are sentences better than paragraphs as information-bearing passages, orare phrases even better? Of particular importance to this invention isthe question of “user involvement.” From the end-user's point of view,making judgements, on the basis of a summary, concerning what a documentis about and whether to pay it closer attention would engage the user ina sequence of actions: look at the summary, absorb its semantic impact,infer what the document might be about, decide whether to consult thesource, somehow call up the full document, and navigate to the point(s)of interest. Given that this introduces a serious amount of cognitiveand operational overhead, what are the implications for the user whenthey are faced with a large, and growing, number of documents to dealwith on a daily basis?

[0008] These are only some of the questions concerning the acceptabilityof summarization technology by end users. There is particular urgency,given the currently evolving notion of “information push”, where contentarriving unsolicited, and in large quantities, at individualworkstations threatens users with real and immediate informationoverload. To the extent that broad coverage summarization techniques arebeginning to get deployed in real world situations, it is still the casethat these techniques are based primarily on sentence extractionmethods. In such a context, the above questions take on more specificinterpretations. Thus, is it appropriate to concatenate together thesentences extracted as representative—especially when they come fromdisjoint parts of the source document? What could be done, within asentence extraction framework, to ensure that all ‘themes’ in a documentget represented by the set of sentences identified by the technology?How can the jarring effect of ‘dangling’ (and unresolved) references inthe selection—without any obvious means of identifying the referents inthe original text—be overcome? What mechanisms could be developed foroffering the user additional information from the document, for morefocused attention to detail? What is the value of the sentence, as abasic information-bearing unit, as a window into a multi-document space?

[0009] To illustrate some of these issues, consider several examplesfrom an operational news tracking site: the News Channel page of Excite,an information vendor and a popular search engine host for the WorldWide Web, which is available via the “Ongoing Coverage” section of thenews tracking page, (http://nt.excite.com). Under the heading ofArticles about IRS Abuses Alleged, some entries read:

EXAMPLE 1

[0010] RENO ON Sunday/Reform Taxes the . . .

[0011] The problem, of course, is that the enemies of the present systemare all grinding different axes. How true, how true, and ditto for mostof the people who sit on the Finance Committee. (First found: Oct. 18,1997)

EXAMPLE 2

[0012] Scheduled IRS Layoffs For 500 Are . . .

[0013] The Agency's original plan called for eliminating as many as5,000 jobs in field offices and at the Washington headquarters. “The waythis has turned out, it works to the agency's advantage, the employees'advantage and the union's advantage.” (First found: Oct. 17, 1997.)

[0014] Both examples present summaries as sentences which almostseamlessly follow one another. While this may account for acceptablereadability, it is at best misleading, as in the original documentsthese sentences are several paragraphs apart. This makes it hard to knowthat the references to “How true, how true”, in the first example, and“The way this has turned out”, in the second, are not whatever might bementioned in the preceding summary sentences, but are, in fact, hiddensomewhere in the original text of the documents. Opening references to“The problem”, and “the agency”, are hard to resolve. The thrust of thesecond article—namely that there is a reversal of an anticipatedsituation—is not at all captured: it turns out that the missingparagraphs between the summary sentences discuss how the planned 5,000layoffs have been reduced to “4,000, then 1,400 and finally settled atabout 500”, and that “now, even those 500 workers will not be cut”. Asit turns out, some indication to this effect might have been surmisedfrom the full title of the article, Scheduled IRS Layoffs For 500 AreCanceled; unfortunately, this has been truncated by a data reductionstrategy which is insensitive to notions of linguistic phrases,auxiliary verb constructions, mood, and so forth.

[0015] In the extreme case, such summaries can range fromunder-informative (as illustrated by the first example above), tomisleading (the second example), to plainly devoid of any usefulinformation. Another example from the same site reads:

EXAMPLE 3

[0016] Technology News from Wired News

[0017] This is more than 500 times thinner than a human hair. “Don'texpect one in a present under your Christmas tree this year.”

[0018] Accordingly, a particular problem that must be addressed is howto “fill in the gaps” which the data reduction process necessarilyintroduces as a summary is constructed by choosing certain fragmentsfrom the original source. Presently, known ways for filling such gaps,assuming of course these are even perceived, is by the active userinvolvement of requesting the entire document.

[0019] Currently, there is a relatively rigid mechanism typicallysensitive to a mouse click, or some similar interactive command, withthe simple semantics of “bring up the entire document, possibly with thepoint of view focused on the particular sentence of the summary whichreceived the click, presented in its natural document context, and maybehighlighted”. Clearly, having a richer data structure would facilitategreater flexibility in interactions with what would be, in effect, awhole range of dynamically reconfigured summaries at different level ofgranularity and detail.

[0020] There is still one problem, however: the process of filling inthe gaps requires active user involvement. In principle there is nothingwrong with this. In practice, real information management environmentsinvolve working with a large number of documents. It is far from clearthat users will have the energy, bandwidth, dedication, andconcentration required to assess, absorb, and act upon summaries foreach one of these documents, by clicking their way through each memberof a long static list.

[0021] Accordingly, what is needed is a system and method for presentinga plurality of documents to a user in a more expeditious fashion thanwhen utilizing conventional techniques. In a preferred embodiment, thesystem and method should be able to analyze documents with multipletopics. The analysis would typically be used to produce summary-likeabstractions of the documents at varying levels of granularity anddetail. The system and method should be easy to implement andcost-effective. Furthermore, the document presentation should containrelevant information from throughout the document, not just a selectionof sentences that may miss significant topics. The system and methodshould allow the presentation to be sensitive to multilayer analysis,should be able to present salient and contextualized highlights of adocument and should make the document available to the user seamlessly,by an active user interface. Finally, the presentation should beadaptable such that a user decides whether he/she desires to be activelyinvolved in the presentation. The present invention addresses theseneeds.

SUMMARY OF THE INVENTION

[0022] A method and system for the dynamic presentation of the contentsof a plurality of documents on a display is disclosed. The method andsystem comprises receiving a plurality of documents and providing aplurality of topically rich capsule overviews corresponding to theplurality of documents. The method and system also includes dynamicallydelivering document content encapsulated in the plurality of capsuleoverviews.

[0023] In so doing, a system and method in accordance with the presentinvention can present thematic capsule overviews of the documents tousers. A capsule overiew is derived for the entire document, which willdepict the core content of an average length article in a more accurateand representative manner than utilizing conventional techniques. Thecapsule overviews, delivered in a variety of dynamic presentation modes,allow the user to quickly get a sense of what a document is about, anddecide whether they want to read it in more detail. If so, the systemand method greatly facilitate the process of focused navigation into theparts of the document which may be of particular interest to the user.

[0024] In a preferred embodiment, the capsule overviews include acontainment hierarchy which relates the different information levels ina document together, and which includes a collection of highly salienttopic stamps embedded in layers of progressively richer and moreinformative contextualized text fragments.

[0025] The novel presentation metaphors which the invention utilizes arebased on notions of temporal typography, in particular for exploitingthe interactions between form and content.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a block diagram illustrating a conventional computersystem that serves as one type of operating environment for the presentinvention.

[0027]FIG. 2 is a simple flow chart illustrating a method for thedynamic presentation of a plurality of documents in accordance with thepresent invention.

[0028]FIG. 3 is a flow chart of a system and method for characterizingthe content of a document in accordance with the present invention.

[0029]FIG. 4 is an example of an article and its segmentation intotopically separate sections.

[0030]FIG. 5 is a depiction of a TopicsTicker in accordance with thepresent invention.

[0031]FIG. 6 is a flow chart of the basic operation of a RSVP viewer inaccordance with the present invention.

[0032]FIG. 7A-7F are depictions of a RAPID SERIAL VISUALIZATIONPRESENTATION (RSVP) viewer in accordance with the present invention.

[0033] FIGS. 8A-8C are depictions of a ViewTool Viewer in accordancewith the present invention.

DESCRIPTION OF THE INVENTION

[0034] The present invention relates to the rapid presentation of thecontent of an average length document. The following description ispresented to enable one of ordinary skill in the art to make and use theinvention and is provided in the context of a patent application and itsrequirements. Various modifications to the preferred embodiment will bereadily apparent to those skilled in the art and the generic principlesherein may be applied to other embodiments. Thus, the present inventionis not intended to be limited to the embodiment shown but is to beaccorded the widest scope consistent with the principles and featuresdescribed herein. A system and method in accordance with the presentinvention would typically be utilized in a conventional computer system.

[0035] Table of Contents

[0036] 1. Overview

[0037] 2. Dynamic Presentation of Document Content

[0038] 2A. Capsule Overviews

[0039] 2B. Salience-Based Content Characterization

[0040] 2C. Anaphora Resolution and Local Salience

[0041] 2D. Discourse Salience and Capsule Overview

[0042] 3. Capsule Overviews as Document Abstractions

[0043] 4. Filling in the Gaps: User Involvement

[0044] 5. Document Characterization by Topics

[0045] 5A. Capsule Overview Example

[0046] 6. Temporal Typography for Dynamic Document Delivery

[0047] 7. Visualization of Document Content

[0048] 8. Dynamic Document Viewers

[0049] 8A. TopicsTicker Viewer

[0050] 8B. Rapid Serial Visual Presentation (RSVP) Viewer

[0051] 8C. ViewTool Viewer

[0052] 8D. Viewer Summary

[0053] 1. Overview

[0054] A system and method in accordance with the present inventionwould typically be utilized in a conventional computer system.

[0055]FIG. 1 is a block diagram illustrating a conventional computersystem 100, which serves as one type of operating environment for thepresent invention. The computer system 100 includes a display 110, akeyboard 120, a pointing device 130, a storage medium 140, a processor150, and a memory 160, which are all connected by a bus 170. Theprocessor 150 operates in conjunction with the memory 160, which are allconnected by a bus 170. The processor 150 operates in conjunction withthe memory 160 to execute a rendering system 180 that enables theprocessor 150 to provide, and present, the content characterization fromtext files stored in some form of computer-readable medium, such as aCD-ROM, or from a network. One of ordinary skill in the art should alsorecognize that the present invention could be utilized in a variety ofdata processing systems, and in particular, display devices, and its usewould be within the spirit and scope of the present invention. Forexample, the present invention could be utilized in Network Computers(NC) and their use would be within the spirit of the present invention.In another example, the present invention could be implemented by aserver utilizing a technique in accordance with the invention to providecontent characterization and a client could provide the resultantdisplay.

[0056] The present invention provides a method and system for utilizingnovel presentation metaphors of documents that enables users to rapidlyskim the documents in order to get the “gist” of their contents. This isaccomplished through the dynamic presentation of topically-rich “capsuleoverviews” of documents. The concept of capsule overviews is describedfully in U.S. application Ser. No. ______ [P2173], entitled, “A Systemand Method for Characterizing Content of Text Documents” filed on evendate herewith, and assigned to the assignee of the present applicationwhich is incorporated by reference in its entirety herein.

[0057] By utilizing the capsule overviews of documents derived by asystem and method in accordance with the teachings of the aboveidentified application, a system and method in accordance with thepresent invention can offer an entirely novel approach to theinformation overload problem. Using topically-rich capsule overviews, asystem and method in accordance with the present invention can presentthematic outlines of the documents to users. These overviews allow theuser to quickly get a sense of what a document is about, decide whetherthey want to read it in more detail, and quickly navigate to thepoint(s) of document of particular interest to them. The followingdiscussion will describe with particularity the dynamic presentation ofdocument content for average length documents.

[0058] 2. Dynamic Presentation of Document Content

[0059]FIG. 2 is a simple flow chart illustrating a method for thedynamic presentation of a plurality of documents in accordance with thepresent invention. As is seen, first a plurality of documents arereceived by a data processing system or the like, via step 202. Next, aplurality of topically rich capsules overviews which corresponds to theplurality of documents, via step 204. Finally a plurality of documentsare presented, via step 206. As before mentioned, by utilizing theabove-described capsule overviews of documents, a system and method inaccordance with the present invention can offer an effective solution tothe information overload problem.

[0060] The solution in accordance with the present invention to theproblem of effectively communicating to the end user the ‘gist’ of anon-line document, or of a collection of on-line documents, is based onthe idea of relating form and content, by means of dynamic visualtreatment of written language, or temporal typography. Only recently hasthe possibility of escaping the static and rigid constraints of writingon paper been fully appreciated. Wong, in Temporal Typography,Characterization of Time-Varying Typographic Forms (Master's thesis, MITMedia Lab, 1995), has stated: “Imagine looking at a small area on acomputer screen. Words appear and disappear on the screen one by one. Asthey appear, meaning is expressed as forms change dynamically over time.The combined effect of the message, form and rhythm express a tone ofvoice, emotion or personality as if you hear a person speak. Althoughthe two mediums, spoken and written words, are vastly different, theanalogy may give you a sense of the expressive potential of temporaltypography.”

[0061] The notion, essentially, is to relate highlights of the coremeaning of a message to ways of visually enhancing their impact, or atleast mimicking (some of) their semantic load. In the immediate contextof this disclosure, this translates to questions of what might beappropriate visual metaphors for representing semantic objects liketopical phrases, shifts in discourse structure, or contextualization ofinformation-bearing phrasal units.

[0062] There are several appealing aspects to dynamically presentingabstractions of document content. The user need not be activelyinvolved: as documents arrive at the desktop, they can be analyzed andthe resulting content abstractions can be displayed autonomously. Shouldthe user have the time or inclination to focus on a particular document,interactive controls will be at their disposal; alternatively, each newarrival can be presented under its own schedule, followed by another,and so on. The presentation cycle can be customized to make use ofarbitrary combinations of granularity of expressiveness. Notions likesemantic highlights and demarcation of context are easily mapped ontovisual metaphors, and thus naturally support the expression of contentby means of variations of form. Cognitively, short phrases with highsemantic load are amenable to punctuated display following a naturalrhythm of visual perception.

[0063] In summary, delivering document content abstractions dynamicallymakes it possible to fully exploit a variable depth analysis ofdocuments (which will be discussed in detail below), maintainssynchronicity with the continuous flow of information into one'spersonal workspace, and allows for smooth integration of passiveabsorption of the analyses by the end-user with active participation inmore focused document perusal.

[0064] The following discussion in accordance with the present inventionhighlights a document analysis technology which seeks to derive documentcontent characterizations designed to exhibit the semantic propertiesdescribed above:

[0065] collections of highly salient topical phrases,

[0066] embedded in layers of progressively richer and more informativecontextualized text fragments,

[0067] with contexts calculated as meaningful fragments defined by acontainment hierarchy of information-bearing phrasal units, and

[0068] organized as capsule overviews which track the occurrence oftopical phrases and other discourse referents across the documentdiscourse.

[0069] Next, some essential features of temporal typography aredescribed, as it relates to dynamic delivery of document content. Theselead into some conclusions about interfaces for content visualizationand, accordingly, a range of viewers designed for the purposes of rapidskimming of on-line documents in order to get the ‘gist’ of theircontents is presented. First, however, the concept of topically-richcapsule overviews is discussed in some detail.

[0070] 2A. Capsule Overviews

[0071] A capsule overview is not a true summary, in that it does notattempt to convey document content as a sequence of sentences. Instead,it is a semi-formal and normalized representation of the document,derived after a process of data reduction over the original text.

[0072] Through capsule overviews, a document's content is characterizedin a way that is representative of the full flow of the document. Thisis in contrast to passage extraction techniques, which typicallyhighlight only certain fragments. Also, capsule overviews are derived bycarrying out linguistically intensive analysis of the text in adocument, which seeks semantic prominence of linguistics expressions,rather than just occurrence of certain pre-specified, or highlyfrequent, words and phrases—thus the system and method described herecan be applied to any document, independent of domain, style or genre.

[0073] A capsule overview is not an instantiated template. A primaryconsideration of the content characterization system and methoddescribed here is that they should not be specific to any documentsource or type. A capsule overview is a coherently presented list oflinguistic expressions which refer to the most prominent objectsmentioned in the document, i.e., its topic stamps, and furthermoreprovide richer specification of the relational contexts (e.g., verbphrases, minimal clauses) in which these expressions appear.

[0074] To further illustrate the concepts associated with a capsuleoverview, refer now to the following news article shown in Table 1.(Marking certain phrase units within single quotes is an annotationdevice, for subsequent references to the text from within thisdisclosure document; these annotations were not part of the originalarticle.) TABLE 1 Priest Is Charged with Pope Attack ‘A Spanish Priest’was charged here today with attempting to murder the Pope. ‘JuanFernandez Krohn’, aged 32, was arrested after ‘a man armed with abayonet’ approached the Pope while he was saying prayers at Fatima onWednesday night. According to the police, ‘Fernandez’ told theinvestigators today that ‘he’ trained for the past six months for theassault. ‘He’ was alleged to have claimed the Pope “looked furious” onhearing ‘the priest's’ criticism of his handling of the church'saffairs. If found guilty, ‘the Spaniard’ faces a prison sentence of15-20 years.

[0075] There are a number of reasons why the title, “Priest Is Chargedwith Pope Attack”, is a highly representative abstraction of the contentof the passage. It encapsulates the essence of what the story is about:there are two actors, identified by their most prominentcharacteristics; one of them has been attacked by the other; theperpetrator has been charged; there is an implication of malice to theact. The title brings the complete set of salient facts together, in athoughtfully composed statement, designed to be brief yet informative.Whether a present day natural language analysis program canderive—without being primed of a domain and genre—the informationrequired to generate such a summary is arguable. (This is assuming, ofcourse, that natural language generation techniques could, in their ownright, do the planning and delivery of such a concise andinformation-packed message.) However, part of the task of deliveringaccurate content characterization is being able to identify thecomponents of this abstraction (e.g., ‘priest’, ‘pope attack’, ‘chargedwith’). It is from these components that, eventually, a true summary ofthis document would begin to be constructed.

[0076] It is also precisely these components, viewed as phrasal unitswith certain discourse properties, that a capsule overview shouldpresent as a characterization of the context of the document.Accordingly, in the present invention, the most salient and thereforemost representative phrasal units, as well as the relational expressionsthey are associated with, are identified to provide the core content ofthe document.

[0077] To describe the generation of capsule overviews in accordancewith the present invention in more detail refer now to FIG. 3 and theaccompanying text. FIG. 3 is a flow chart of a system and method forcharacterizing the content of a document in accordance with the presentinvention. As is seen in the figure, first a list of discourse referentsare provided within the document via step 302. Then, the document isdivided into separate segments based upon changes in topic, via step304. Thereafter, the discourse referents are linked together intoco-reference classes, via step 306. Next, the salience for each of thediscourse referents is calculated, via step 308. After thosecalculations are performed, then it is determined which discoursereferents have the highest values within a segment, via step 310. Thecore information unit that the invention concerns itself with is the setof discourse referents in a document. Discourse referents are typicallyrealized as noun phrases. In essence, these are the entities—actors andobjects—around which a story unfolds. In order to determine, andmaintain, an accurate model of what a document is about, it is necessaryto be able to identify the ways in which the same entity is referred toin the text, as well as to establish co-referentiality among different‘mentions’ in the text of the same entity. The sample document in Table1 provides examples of the same entity being referred to in differentways in the text (“priest”, “a Spanish Priest”, “Fernandez”, and “he”,in the second paragraph, all refer to the same person), as well as ofdifferent entities being referred to by the same text string (“he” inthe first paragraph refers to the Pope, while “he” in the secondparagraph refers to the priest).

[0078] Thereafter, discourse referents with the highest salience valuesare labeled as topic stamps, via step 312. The local contexts aroundeach of the topic stamps are identified, via step 314. Finally, fromthis information a capsule overview of the document is constructed witha given degree of granularity via step 316. A key concept associatedwith generation of the capsule overviews is the calculation of saliencevalues for the discourse referents, which are then used for determiningtopic stamps in the document. The following will discuss salience basedcalculations in more detail.

[0079] 2B. Salience-Based Content Characterization

[0080] Salience is a measure of the relative promience of objects indiscourse: objects with high salience are the focus of attention; thosewith low salience are at the periphery. In an effort to resolve theproblems facing a term-based approach to content characterization, asdiscussed in the background of the application, a procedure inaccordance with the present invention has been developed which uses asalience feature as the basis for a “ranking by importance” of anunstructured referent set; ultimately, this facilitates topic stampidentification. By determining the salience of the members of a referentset, an ordering can be imposed which, in connection with an appropriatechoice of threshold value, permits the reduction of the entire referentset to only those expressions that identify the most prominentparticipants in the discourse. This reduced set of terms, in combinationwith information about local context at various levels of granularity(verb phrase, minimal clause, sentence, etc.) offers an accurate anddetailed characterization of a document's content. This may then befolded into an appropriate presentation metaphor such as that will bedescribed hereinafter. Crucially, such an analysis satisfies someimportant requirements of usability of document content abstractions: itis concise, it is coherent, and it does not introduce cognitiveoverload. In a more general sense, this method utilizes a strategy forscaling up the phrasal analysis techniques utilized by standard termidentification and template instantiation technologies, which has at itscore the utilization of a crucial feature of discourse structure: theprominence, over some segment of text, of particular referents—somethingthat is missing from the traditional technology for ‘bare’ terminologyidentification.

[0081] 2C. Anaphora Resolution and Local Salience

[0082] For the purposes of determining how discourse referents relate toobjects in the world of the document, a simplifying assumption is madethat every noun phrase identified by extended phrasal analysisconstitutes a “mention” of a participant in the discourse. In order todetermine which expressions constitute mentions of the same referent,the method described here crucially relies upon being able to carry outanaphora resolution and co-referent identification. Linguisticexpressions that are identified as coreferential are grouped intoequivalence classes, and each equivalence class is taken to represent aunique referent in the discourse. The set of such equivalence classesconstitutes the full referent set from which, ultimately, topic stampswill be derived.

[0083] A distinctive feature of the anaphora resolution algorithm isthat it has been specially adapted to work from a shallow syntacticbase: specifically, it does not require full syntactic analysis of thetext. This makes the method applicable to any text document,irrespective of its domain, style, or genre. This type of anaphoraresolution algorithm is described, in full detail, in the paper“Anaphora for Everyone: Pronominal Anaphora Resolution Without aParser,” by C. Kennedy and B. Boguraev, which was presented at the 16thInternational Conference on Computational Linguistics, Copenhagen,Denmark, Aug. 5-9, 1996.

[0084] The immediate result of anaphora resolution is to reduce theextended phrase set of all mentions of objects in the discourse; thelarger consequence is that it provides the basis for the identificationof topic stamps, as it introduces both a working definition of salienceand a formal mechanism for determining the salience of particularlinguistic expressions. This connection between anaphora resolution,co-reference identification, discourse salience, and semantic prominenceis described in fuller detail in “Anaphora for Everyone: PronominalAnaphora Resolution Without a Parser,” (C. Kennedy and B. Boguraev, inProceedings of COLING-96 (16th International Conference on ComputationalLinguistics), Copenhagen, DK, Aug. 5-9, 1996) and “Anaphora in a WiderContext: Tracking Discourse Referents” (C. Kennedy and B. Boguraev, inW. Wahlster, Editor, Proceedings of ECAI-96 (12th European Conference onArtificial Intelligence), Budapest, Hungary, Aug. 11-16, 1996. JohnWiley and Sons, Ltd., London/New York).

[0085] Roughly speaking, the anaphora resolution procedure locates anantecedent for an anaphoric expression by first eliminating allimpossible candidate antecedents, then ranking the remaining candidatesaccording to a salience measure and selecting the most salient candidateas the antecedent. This measure, which is referred to as ‘localsalience’, is a function of how a candidate antecedent expressionsatisfies a set of grammatical, syntactic, and contextual parameters.These constraints are typically referred to as “salience factors”.Individual salience factors are associated with numerical values, asshown below. TABLE 2 “sent”: 100 iff the expression is in the currentsentence. “cntx”:  50 iff the expression is in the current discoursesegment. “subj”:  80 iff the expression is a subject. “exst”:  70 iffthe expression is in an existential construction. “poss”:  65 iff theexpression is a possessive. “acc”:  50 iff the expression is a directobject. “dat”:  40 iff the expression is an indirect object. “oblq”:  30iff the expression is the complement of a preposition. “head”:  80 iffthe expression is not contained in another phrase. “arg”:  50 iff theexpression is not contained in an adjunct.

[0086] The local salience of a candidate is the sum of the values of thesalience factors that are satisfied by some member of the equivalenceclass to which the candidate belongs; values may be satisfied at mostonce by each member of the class. The most important aspect of thesenumerical values for our concerns is that they impose a relationalstructure on the salience factors, which in turn provides the basis forordering referents according to their relative prominence in thediscourse (in other words, what is important is not so much the valuesthemselves but the fact that they denote that, for instance, “subj”factor indicates higher prominence than “acc”, itself more prominentthan “oblq”, and so forth).

[0087] 2D. Discourse Salience and Capsule Overviews

[0088] An important feature of local salience is that it is variable:the salience of a referent decreases and increases according to thefrequency with which it is mentioned (taking into account subsequentanaphoric expressions). When an anaphoric link is established, theanaphor is added to the equivalence class to which its antecedentbelongs, and the salience of the class is boosted accordingly. If areferent ceases to be mentioned in the text, however, its local salienceis incrementally decreased; this reflects decay in its prominence. Thisapproach works well for the purpose of anaphora resolution, because itprovides a realistic representation of the antecedent space for ananaphor by ensuring that only those referents that have mentions withina local domain have increased prominence. However, the ultimate goal ofsalience-based content characterization differs from that of anaphoraresolution in an important respect. In order to determine whichlinguistic expressions should be presented as broadly representative ofthe content of a document, it is necessary to generate a picture of theprominence of referents across the entire discourse, not just within alocal domain.

[0089] For illustration of the intuition underlying this idea, considerthe news article discussed in Table 1. Intuitively, the reason why“priest” is at the focus of the title is that there are no less thaneight references to the same actor in the body of the story (marked bysingle quotes in the example); moreover, these references occur inprominent syntactic positions: five are subjects of main clauses, twoare subjects of embedded clauses, and one is a possessive. (This examplealso illustrates the rationale behind the above-described saliencefactors.) Similarly, the reason why “Pope attack” is the secondaryobject of the title is that a constituent of the compound, “pope”, alsoreceives multiple mentions (five), although these references tend tooccur in less prominent positions (two are direct objects).

[0090] In order to generate the broader picture of discourse structureneeded to inform the selection of certain expressions as most salient,and therefore most representative of content, an elaboration isintroduced of the local salience computation described above that usesthe same conditions to calculate a non-decreasing, global salience valuefor every referent in the text. This non-decreasing salience measure,which is referred to as ‘discourse salience’, reflects thedistributional properties of a referent as the text story unfolds. Inconjunction with the “tracking” of referents made available by anaphoraresolution—as discussed at some length in “Anaphora in a wider context:Tracking discourse referents” (C. Kennedy and B. Boguraev, in W.Wahlster, editor, Proceedings of ECAI-96 (12th European Conference onArtificial Intelligence), Budapest, Hungary, Aug. 11-16, 1996. JohnWiley and Sons, Ltd, London/New York)—discourse salience provides thebasis for a coherent representation of discourse structure thatindicates the topical prominence of individual mentions of referents inisolated segments of text.

[0091] Most importantly, discourse salience provides exactly theinformation that is needed to impose the type of importance-basedranking of referents which is required for the identification of topicstamps. Specifically, by associating every referent with a discoursesalience value, the topic stamps can be identified for a segment of textS as the n highest ranked referents in S, where n is a scalable value.

[0092] The notion “segment of text” plays an extremely important role inthe content characterization task, as it provides the basicinformation-structuring units around which a capsule overview for adocument is constructed. Again, the example from Table 1 gives a usefulillustration of the important issues. The reason that the title of thispassage works as an overview of its content is because the text itselfis fairly short. As a text increases in length, the “completeness” of ashort description as a characterization of content deteriorates. If theintention is to use concise descriptions consisting of one or twosalient phrases—i.e., topic stamps—along with information about thelocal context in which they appear as the primary information-bearingunits for a capsule overview, then it follows that texts longer than afew paragraphs must be broken down into smaller units or “segments”.

[0093] In order to solve this problem, a document is recast as a set of“discourse segments”, which correspond to topically coherent, contiguoussections of text. One approach to segmentation which works well for thepurposes of this method implements a similarity-based algorithm alongthe lines of that described by Hearst, in her paper entitled“Multi-Paragraph Segmentation of Expository Text.” (M. Hearst, in 32ndAnnual Meeting of the Association for Computational Linguistics, LasCruces, N.M., 1994), which identifies discourse segments in text using alexical similarity measure. By calculating the discourse salience ofreferents with respect to the results of discourse segmentation, eachsegment can be associated with a listing of those expressions that aremost salient within the segment, i.e., each segment can be assigned aset of topic stamps. The result of these calculations, namely the set ofsegment-topic stamp pairs, ordered according to linear sequencing of thesegments in the text, can then be returned as the capsule overview forthe entire document. In this way, the problem of contentcharacterization of a large text is reduced to the problem of findingtopic stamps for each discourse segment.

[0094] 3. Capsule Overviews as Document Abstractions

[0095] Striving to balance the conflicting requirements of depth andaccuracy of a summary with those of domain- and genre-independence, thenotion of a capsule overviews has been developed as content abstractionfor text documents, explicitly designed to capture “aboutness”. One ofthe problems of information management, when presented with a growingsurplus of text documents, is getting some appreciation—rapidly,compactly, and yet with a usable degree of depth andrepresentativeness—of the information contained in a document.Informally, this is usually referred to as the “aboutness” of adocument, and is represented as a set of highly salient, and by thattoken most representative, phrases in the document. By viewingtopicality in its stricter, linguistic, sense, the previous sectiondefined topic stamps to be the most prominent of these phrases,introduced into, and then elaborated upon, the document body. On thebasis of this definition, the above-identified computational,algorithmic, procedure has been developed for generating a set ofabstractions for the core meaning in the document, ultimately resultingin a capsule overview of the document based upon suitable presentationof the most representative, and most contentful, expressions in thetext. These abstractions comprise layered and inter-related phrasalunits at different levels of granularity and depth of document analysis.To further describe this concept of granularity refer now to thefollowing discussion.

[0096] Granularity is closely tied to context. In general, theinformation in a given sentence is best expanded by being able toposition this sentence in its paragraph context; likewise, the theme andtopic(s) in a paragraph can be further elaborated by relating theparagraph to the segment of discourse which encompasses the theme in itsentirety. This is a natural containment hierarchy, relating thedifferent information levels in a document together. Such a hierarchycan also be extended in sub-sentential direction: phrasal unitsindicative of topicality are clearly wholly contained in sentences;furthermore, a phrasal containment hierarchy could also be utilized toprovide contextualized information concerning the topical phrasesthemselves.

[0097] Imagine that in the second example above (Example 2, page 5) somemechanism has determined that the phrase “Scheduled IRS Layoffs” istopically indicative. Assuming some focused mining in the vicinity ofsuch an ‘anchor’ by a phrasal grammar of a certain type, this topicphrase could be further contextualized to “Scheduled IRS Layoffs For 500Are Canceled”. This is an example of phrasal containment ofinformation-bearing phrasal units. Similar expansion of topic in contextmight yield, for the initial discourse segment of the document,progressively larger and more informative fragments from it:

EXAMPLE 4

[0098] TOPICAL PHRASE: “Scheduled IRS Layoffs” TOPIC IN RELATIONAL“there will be no layoffs” CONTEXT: TOPICAL SENTENCE: “Yesterday, theIRS said there will be no layoffs” SENTENCE IN PARAGRAPH CONTEXT: “Morethan a year ago, The Internal Revenue Service planned widespread jobcuts. Yesterday, the IRS said there will be no layoffs.” PARAGRAPHWITHIN TOPICALLY COHERENT DISCOURSE THEME: “More than a year ago, theInternal Revenue Service planned widespread job cuts. Yesterday, the IRSsaid there will be no layoffs.” Confronted with congressional criticismand calls for reform in light of some highly publicized reports ofabusive actions toward taxpayers, as well as staunch union opposition tothe cuts, the IRS said employees at risk of losing their jobs would bereassigned to improve ‘customer service,’ help taxpayers resolveproblems and increase compliance with tax laws.”

[0099] This example illustrates the notion of granularity of documentanalysis, and is especially indicative of how a containment hierarchy oflayered information—from very compact and representative topical phrasesall the way to full and rich discourse segments—can be utilized torepresent and maintain strong notion of contextualization in a documentabstraction.

[0100] The example also shows the value of being able to identifyphrasal units smaller than sentences, arrange them in layerscorresponding to the informational containment hierarchy, and performcertain semantic operations over them. These operations fall largely inthe area of reference identification, co-referentiality, and topictracking; consider, for example, the processes of relating “layoffs” to“scheduled IRS layoffs”, identifying “Internal Revenue Service” and“IRS” as referring to the same object, resolving anaphora in general,and so forth.

[0101] 4. Filling in the Gaps: User Involvement

[0102] It is clear that granularity of analysis and containmenthierarchy of information-bearing phrasal units with different (yetcomplementary) discourse properties and function could be utilized veryeffectively to implement a “zooming” function into and/or out of a givendocument. In this way finding out more of what is behind a document“summary” is, in effect, filling in the gaps in such a summary in acontrolled fashion, guided by incrementally revealing progressivelylarger and more informative contexts.

[0103] Conceptually, this is not dissimilar to the notion of “percentageof shrink factor”, typically utilized by sentence-based summarizes,where a user can specify that a document should be condensed to Npercent of its full extent. There is, however, a crucial differencehere. When re-casting a document from, say, 10% to 20% shrink factor,there is no way to specify ahead of time, nor to know after the event,how the additional sentences relate to the original 10%. In contrast,when a document is re-cast in terms of information-bearing units a levelhigher than what its current representation uses—for instance, as a setof relational contexts immediately surrounding its topic stamps—there isa guarantee that the user's sense of what the document is about isincrementally and monotonically enriched.

[0104] This makes it possible to use the capsule overview technology inaccordance with the present invention to enable a user to get animmediate and accurate impression of what a particular document isabout. As a capsule overview is a small window into the core content ofa document, it is a useful abstraction for compact representation ofcontent. Once engaged, however, the user can still use this window to‘drill’, arbitrarily deeply, into the underlying information layers.Before discussing the approach to visualization of document content andpresentation metaphors for using capsule overviews as mediators, andfacilitators, of dynamic document content delivery, the basic notions oftopically rich capsule overviews as layered abstractions of documentcontent are exemplified hereinbelow.

[0105] 5. Document Characterization by Topics

[0106] 5.A. Capsule Overview Example

[0107] The following discussion describes an example of an article theanalysis of which utilizes the present invention. As described insections 2 and 3 above, the operational components of salience-basedcontent characterization fall in the following categories: discoursesegmentation; phrasal analysis (of nominal expressions and theirrelational contexts); anaphora resolution and generation of a referentset; calculation of discourse salience and identification of topicstamps; and enriching topic stamps with information about relationalcontext(s). Some of the functionality follows directly from technologydeveloped for the purposes of phrasal identification, suitably augmentedwith mechanisms for maintaining phrase containment; in particular, bothrelation identification and extended phrasal analysis are carried out byrunning a phrasal grammar over a stream of text tokens tagged forlexical, morphological, and syntactic information, and for grammaticalfunction; this is in addition to a grammar mining for terms and,generally, referents.

[0108] In a preferred embodiment the base level linguistic analysis isprovided by the LINGSOFT supertagger; see F. Karlsson, A. Voutilainen,J. Heikkila, and A. Antilla, “Constraint Grammar: A Language-IndependentSystem for Parsing Free Text”, Mouton de Gruyter, 1995. The later, moresemantically-intensive algorithms are described in detail in “Anaphorafor Everyone: Pronominal Anaphora Resolution Without a Parser” (C.Kennedy and B. Boguraev, in Proceedings of COLING-96 (16th InternationalConference on Computational Linguistics), Copenhagen, DK, 1996) and“Anaphora in a Wider Context: Tracking Discourse Referents” (C. Kennedyand B. Boguraev, in W. Wahlster, editor, Proceedings of ECAI-96 (12thEuropean Conference on Artificial Intelligence), Budapest, Hungary,1996. John Wiley and Sons, Ltd, London/New York). The procedure isillustrated by highlighting certain aspects of a capsule overview of anarticle 400 shown in FIG. 4. The document is of medium-to-large size(approximately four pages in print), and focuses on the strategy ofGilbert Amelio (former CEO of Apple Computer) concerning a new operatingsystem for the Macintosh. Too long to quote here in full, the followingpassage from the beginning of the article contains the first, second andthird segments (shown at 402, 404, and 406 in FIG. 4), as identified bythe discourse segmentation component. (In the figure, segment boundariesare marked by extra vertical space; this markup is for illustrationpurposes only, and indicates the result of running the discoursesegmentation algorithm. No such demarcation exists in the source of thearticle itself).

[0109] The capsule overview was automatically generated by a fullyimplemented, and operational, system, which incorporates all of theprocessing components identified above. The relevant sections of theoverview of the article 400 (for the three segments of the passagequoted) are shown in Tables 3, 4 and 5 below.

[0110] The topic stamps for the three segments 402, 404, and 406constitute the core data out of which a capsule overview is constructed;these are shown underlined immediately following the segment sequenceidentifiers (in square brackets). The capsule overview itself displaysthe topic stamps (highlighted in single quotes) in their relationalcontents. TABLE 3 [1] Apple; Microsoft ‘Apple’ would swoop in and take‘Microsoft's’ customers? ‘Apple’ lost $816 million; ‘Microsoft’ made$2.2 billion. ‘Microsoft’ has a market value thirty times that of‘Apple’ it makes sense for ‘Apple’ ‘Apple’ is in a position ‘Apple’needs something dramatic

[0111] TABLE 4 [2] desktop machines; operating system Today's ‘desktopmachines’, he [Gilbert Amelio] says Tomorrow's ‘machines’ mustaccommodate rivers of data Time to scrap your ‘operating system’ andstart over The ‘operating system’ is the software that controls to gowith the ‘reengineered operating system’

[0112] TABLE 5 [3] Gilbert Amelio; new operating system ‘Ameilo’, 53,brings a lot of credibility to this task ‘His’ [Gilbert Amelio] resumeincludes where is ‘Amelio’ going to get this ‘new operating system’?radical redesign in ‘operating systems’ that ‘Amelio’ is talking about

[0113] The division of this passage into segments, and the segment-basedassignment of topic stamps, exemplifies a capsule overview's “tracking”of the underlying coherence of a story. The discourse segmentationcomponent recognizes shifts in topic—in this example, the shift fromdiscussing the relation between Apple and Microsoft to some remarks onthe future of desktop computing to a summary of Amelio's background andplans for Apple's operating system. Layered on top of segmentation arethe topic stamps themselves, in their relational contexts, at a phrasallevel of granularity.

[0114] The first segment (Table 3) sets up the discussion by positioningApple opposite Microsoft in the marketplace and focusing on their majorproducts, the operating systems. The topic stamps identified for thissegment, “apple” and “microsoft”, together with their local contexts,are both indicative of the introductory character of the openingparagraphs and highly representative of the gist of the first segment.Note that the apparent uninformativeness of some relational contexts,for example, “. . . ‘Apple’ is in a position . . . ”, does not pose aserious problem. An adjustment of the granularity—at capsule overviewpresentation time (see below)—reveals the larger context in which thetopic stamp occurs (e.g., a sentence), which in turn inherits the hightopicality ranking of its anchor: “‘Apple’ is in a position wherestanding pat almost certainly means slow death.”

[0115] For the second segment (Table 4) of the sample, “operatingsystem” and “desktop machines” have been identified as representative.The set of topic stamps and contexts illustrated provides anencapsulated snapshot of the segment, which introduces Amelio's views oncoming challenges for desktop machines and the general concept of anoperating system. Again, even if some of these are somewhatunder-specified, more detail is easily available by a change ingranularity, which reveals the definitional nature of the even largercontext “The ‘operating system’ is the software that controls how yourcomputer's parts . . . ”

[0116] The third segment (Table 5) of the passage exemplified above isassociated with the stamps “Gilbert Amelio” and “new operating system”.The reasons, and linguistic rationale, for the selection of theseparticular noun phrases as topical are essentially identical to theintuition behind “priest” and “Pope attack” being the central topics ofthe example in Table 1. The computational justification for the choiceslies in the extremely high values of salience, resulting from takinginto account a number of factors: co-referentiality between “amelio” and“Gilbert Amelio”, co-referentiality between “amelio” and “his”,syntactic prominence of “amelio” (as a subject) promoting topical statushigher than for instance “Apple” (which appears in adjunct positions),high overall frequency (four, counting the anaphor, as opposed to threefor “Apple”—even if the two get the same number of text occurrences inthe segment), and boost in global salience measures, due to “priming”effects of both referents for “Gilbert Amelio” and “operating system” inthe prior discourse of the two preceding segments. Compared to a singlephrase summary in the form of, say, “Amelio seeks a new operatingsystem”, the overview for the closing segment comes close; arguably, itis even better than any single phrase summary.

[0117] As the discussion of this example illustrates, a capsule overviewis derived by a process which facilitates partial understanding of thetext by the user. The final set of topic stamps is designed to berepresentative of the core of the document content. It is compact, as itis a significantly cut-down version of the full list of identifiedterms. It is highly informative, as the terms included in it are themost prominent ones in the document. It is representative of the wholedocument, as a separate topic tracking module effectively maintains arecord of where and how referents occur in the entire span of the text.As the topics are, by definition, the primary content-bearing entitiesin a document, they offer accurate approximation of what that documentis about.

[0118] 6. Temporal Typography for Dynamic Document Delivery

[0119] Dynamic content delivery is based on ideas of temporal typographydeveloped by Wong (Y. Y. Wong, Temporal typography, characterization oftime-varying typographic forms, Master's thesis, MIT Media Lab, 1995).This work develops a synergy of psychological studies of reading,graphic design, and temporal presentation of text. Graphic designhistory is rich with examples of experimenting with visual treatment ofwritten language. Designers have begun to explore temporal presentationof text in television and film media. Studies of reading, which to alarge extent form the basis of Wong's work, have explored dynamicpresentation of content, related to the interactions between meaning andintent of a text-based message. However, Wong's studies of the dynamicrelationship between meaning and delivery formats assume that theannotations for meaning in her experiments have been done by hand. Incontrast, this invention is concerned with leveraging an automaticdocument content analysis technology, capable of delivering meaninganalyses and content abstractions precisely of the kind which can beeffectively coupled with dynamic content delivery.

[0120] 7. Visualization of Document Content

[0121] Previously, the predominant current mechanism for mediating thespectrum between a summary of a document and a complete version of thesame document was briefly discussed, In addition to a direct hypertextrendering of extracted sentences, in their full document contexts, twovariations on this approach are the VESPA slider and HYPERGEN. VESPA isan experimental interface to Apple's sentence-based summarizer (AdvancedTechnologies Group, Apple Computer, Cupertino, Calif., Apple InformationAccess Toolkit: Developer Notes and APIs, 1997), whose main feature is aslider which dynamically readjusts the shrink factor of a documentsummary. HYPERGEN exploits notions of phrasal containment withinsentence units, in an attempt to elaborate a notion similar to that ofgranularity of analysis and context introduced earlier in this document:in a process called sentence simplification, Mahesh (K. Mahesh,Hypertext summary extraction for fast document browsing, in Proceedingsof AAAI Spring Symposium on Natural Language Processing for the WorldWide Web, pages 95-104, Stanford, Calif., 19975) uses phrases as“sentence surrogates”, which are then straightforwardly rendered ashypertext links to the sentences themselves.

[0122] As part of an ongoing investigation of visualizing largeinformation spaces, researchers at Xerox PARC have looked at a varietyof structured data types (such as hierarchically structured data,calendars, and bibliographic databases). Some general principles derivedfrom that work have been applied to unstructured documents: the DOCUMENTLENS is a technique for viewing 2-D information, designed for componentpresentations of multi-page documents. Without going into detail, whatis of particular relevance here is the strong notion of focus pluscontext which drives the design. The visualization, however, does littlein terms of using any kind of document summary or other abstraction, andis of a predominantly static nature (even though it is extremelyresponsive to user interaction, as it attempts to combine a ‘bird's eyeview’ of the entire document with a page browsing metaphor). Morerecently experimental prototypes have been developed for interfaceswhich treat term sets (in the information retrieval sense, i.e. flatlists of index terms) as document surrogates: the focus of such designsis visually on presenting notions like distribution of terms across thedocument, and on mediating access to local context for a given term (RRao, J. O. Pedersen, M. A. Hearst, J. D. Macinlay, S. K. Card, L.Masinter, P.-K. Halvorsen, and G. G. Robertson, “Rich interaction in thedigital library”, Communication of the ACM, 38(4):29-39, 1995; M. A.Hearst, “Tilebars: Visualization of term distribution information infull text information access,” in ACM SIGCHI Conference on Human Factorsin Computing Systems, Denver, Colo., 1995). Ultimately, however, theseinterfaces still offer only a direct link between two states, thedocument surrogate and its full form.

[0123] With the migration of news delivery over the World Wide Web andthe growth of information ‘push’ vendors, some new methods are beginningto emerge for presentation of news stories which use notions of dynamicdelivery of content. Most of these are variations on the same theme:news delivery using a ticker metaphor. Thus both ABC's news site(http://www.abc.com) and Pointcast (http://www.pointcast.com) employ atraditional horizontal ticker, CNN Interactive (http://www.cnn.com)arrange their ticker vertically, while CBS (http://www.uttm.com) combinea ticker with photos from a major story.

[0124] The important insight here is that tickers are dynamic objects,which can be programmed to continuously update themselves from a newsfeed and to cycle in a pre-defined regime, therefore not requiring userintervention. Furthermore, they can be dispatched to an area of theworkspace (monitor screen) where constant, yet inobtrusive, newsdelivery can take place in the periphery of the user's main activity:thus a choice exists between proactive engagement with the news source,and passive (and almost subliminal) monitoring of news data.

[0125] None of the examples above, however, combines a ticker with anautomatic summarization engine. To a large extent this is becausesentences—especially inconsecutive ones, in the absence of visualmarkers for discontinuity—do not lend themselves easily into the word byword, left to right, presentation mode. This is clearly a situationwhere phrasal units of a sub-sentence granularity can be utilized muchmore effectively. In addition, psychological experiments on activereading (Y. Y. Wong, Temporal typography, characterization oftime-varying typographic forms, Master's thesis, MIT Media Lab, 1995)show that when text is presented dynamically in the manner of a ticker,subjects' reading speeds are significantly slower than for textpresented statistically. On the other hand, dynamic presentations oftext which show words or short phrases in the same location, butserially, one after the other, have reading speeds comparable to thosefor normal static texts.

[0126] To date, no applications have been developed utilizing temporaltypography for dynamic delivery of content abstractions. Wong has lookedat how dynamic type in general can be used for four differentcommunicative goals: expressive messages, dialogue, active reading andreal time conversation. Most relevant to this discussion are herexperiments on active reading. In one of these she used a basic RSVP(Rapid Serial Visual Presentation) method (words or phrases presentedsequentially one after another, on the same line and at the sameposition) to deliver a sequence of news headlines. In a second set ofexperiments called HIGHWAY NEWS, three dimensions are utilized, combinedwith a zooming motion, to present a sequence of text highlights. “Newsheadlines are placed one after another in the z-dimension. Headlines arepresented serially according to active input from the a reader presses amouse button to fly through the rows of headlines—as if flying overhighway of text.” These experiments show the strong feasibility of highimpact, low engagement, delivery of semantically prominent textfragments being utilized as a powerful technique for visualizing certaintypes of inherently linear information.

[0127] None of the work cited above relies on automatically generatedmeaning abstractions as its input; yet, it is clear that thetopically-rich capsule overviews generated by the document analysistechnology discussed in sections 2 and 3, and exemplified in section 5,are just the kind of semantic highlights which Wong's experiments inactive reading assume. Conversely, up till now there has been no thoughtas to how the nature of topic-based capsule overviews in particularwould fit the notion of dynamic type. This is a key feature of thepresent invention, and is discussed below.

[0128] 8. Dynamic Document Viewers

[0129] Below will be described three embodiments of systems or viewersfor providing dynamic presentation of documents. These three embodimentswill be hereinafter referred to as the TopicsTicker Viewer, Rapid SerialVisual Presentation (RSVP) Viewer and the ViewTool Viewer. It should beunderstood that although these three viewers are described, one ofordinary skill in the are recognizes a variety of views could beutilized and they would be within the spirit and scope of the presentinvention. To more particularly describe these embodiments refer now tothe following discussion in conjunction with the accompanying Figures.

[0130] The above three embodiments provide different dynamic views ofdocument content. The difference is largely due to the variety ofoperational environments in which the viewers have been applied. Avariation on a news ticker is designed to be deployed in situationswhere screen real estate may be at premium, or where several differentchannels of information may be delivered simultaneously to the same‘in-box’; typically such situations assume that users would only want toget a very general idea of document content. For situations where morescreen real estate might be available, and/or it may be known ahead oftime that more detail concerning document content might be required, adifferent viewer develops ideas from rapid serial visual presentation(RSVP). Yet another interface caters to the need to be able to getimmediate access to the full text of a document, without losing thebenefits of rapid skimming through content highlights while fullymaintaining information about the larger context.

[0131] All of the viewers assume an environment where incoming documentsget analyzed to capsule overview level (See FIG. 3); the results of theanalysis are embedded into the original text by means of for example,special purpose tags.

[0132] 8A. TopicsTicker Viewer

[0133] TopicsTicker Viewer as shown in FIG. 5 is a minimalist,hands-free, peripheral-vision-directed ticker tape, with certain aspectsof its display tuned for serial delivery of a document's topic stamps:the string in the left panel is the document title, and the right panelis where the display cycles, continuously, through the document's topicstamps. When running over a set of documents, switching from onedocument to the next is cued by a color change and a vertical scroll.

[0134] 8B. Rapid Serial Visual Presentation (RSVP) Viewer

[0135]FIG. 6 is a flow chart of the operation of the RSVP viewer. First,a list or plurality of consecutively ordered documents are provided, viastep 602. Next, the first document in order is selected, via step 604.Thereafter, the first topic stamp from the current document is selectedfrom the capsule overview, via step 606. The relational context for thattopic stamp is selected from the capsule overview, via step 608. Thecanonical form for that topic stamp is retrieved, via step 610. Then thetopic stamp is displayed in the background, in translucent type, and itsassociated relational context is displayed in the foreground, in heaviertype, via step 612. Next, a time period for displaying the relationalcontext is calculated, via step 614. This time period is based upon theamount of information displayed. The topic stamp and relational contextare then displayed for that time period, via step 616. It is thendetermined if there are other topic stamps, via step 618. If there areother topic stamps, then the next topic stamp is selected, via step 620and its associated relational context is selected, via step 608, and thecycle is repeated. If on the other hand, there are no other topicstamps, a visual worker is displayed, indicating a document change, viastep 622. It is then determined if there are other documents, via step624. If there are no other documents then recycle back from the firstdocument. If there are other documents, then the next document inconsecutive order is selected, via step 626. Thereafter, its first topicstamp is selected, via step 606, and the cycle is repeated.

[0136] This continuous cycle defines the basic mode of operation forRSVP viewer. It can, as will be discussed below, be interrupted by theuser at any time.

[0137] In its basic mode with no user interaction, the RSVP Viewercycles through all salient relational contexts in a document,maintaining the order in which they appear in the text. As shown inFIGS. 7A-7B, each context phrase is displayed as the prominent object onthe screen 702; at the same time the context is overlaid onto topicexpansions (displayed as translucent text) 704. This facilitates furtherinterpretations of the context strings by the user: expansions relatephrasal contractions in the string displayed to their full canonicalforms in the text, make clear antecedents of dangling anaphors, and soforth. Note, for instance, the background display (FIG. 7C) 704 of thefull form of the antecedent for the anaphoric “he” in the foreground702: in this particular context, “he” has been resolved to “GilbertArmelio”.

[0138] Cycling though the complete set of salient contexts, in theiroriginal sequence, offers a good indication of aboutness at a givenlevel of depth and detail. Granularity of display is adjustable via aparameter: thus RSVP Viewer could be reduced to a TopicsTicker Viewer byonly cycling through the document's topic stamps, or it could be used todisplay sequences of sentences. Relational contexts offer just the rightbalance between terseness (phrases are more easily perceived andassimilated than sentences) and informativeness (phrases larger than‘bare’ topic stamps convey richer data). The amount of time a phrase isdisplayed is dynamically calculated, based on studies of active readingand perception; the intent is to optimize the full document displayregime so that individually, each phrase can be processed by the user,while globally, the entire set of salient contexts can be cycled throughrapidly.

[0139] There are provisions for maintaining overall context, bycontinuously displaying the title of the current document 706, as wellas for allowing context switching, by user selection of a document froma pop-up menu 708 (co-located with the title), via for example by amouse click.

[0140] RSVP Viewer is designed as an entirely autonomous viewer: afterall the content highlights in a document have been displayed, the nextdocument will be loaded and the cycle repeated (just like inTopicsTicker Viewer, a suitable visual cue signals document change).This makes it very appropriate for situations where readers do not havemuch time, bandwidth, or opportunity, to interact with the display, butthey would want to be peripherally aware of new documents that come intothe system. On the other hand, if a particular context catches the userattention, a ‘zoom’ mechanism makes use of the multiple levels ofanalysis of the document (as defined via the containment hierarchydiscussed in Section 3, “Capsule Overviews as Document Abstractions”).

[0141] This will reveal, on demand, progressively larger and more welldetailed document fragments: sentences, paragraphs and segments. FIGS.7B, 7D and 7E viewed in this sequence give an indication of howprogressively informative contexts are revealed on demand: 7B displays atopic and its content, in FIG. 7D the latter is contextualized to thesentence containing it and in FIG. 7E, this sentence is displayed in thecontent of the relevant (containing) paragraph. Foreground andbackground information are always differentiated by hierarchies of type.The transition between displays—e.g., from 7B to 7D, or from 7D to 7E,is accentuated by a visual “zoom” mechanism. In such a hierarchy, aboutthe larger context is always easily available: for instance, furtherspecifics concerning what “he says” (see FIG. 7c) is immediatelyavailable by a single click in the display area, the result of which isshown in FIG. 7F.

[0142] At any given point of time, and depth of detail, the display usesa combination of visual cues to highlight the information-bearing unitwhich is in focus, and associate this with the larger context in whichit appears in the original source. In particular, properties of type,both static and dynamic, come to convey various aspects of the documentanalysis: primary focus of attention is denoted by using heavy blacktypeface; background context, by using translucent text; semanticrelatedness, by overlaying the focus and context onto the same displayarea; different level of attention to detail by visually andperceptibly, zooming in when more detail is requested, and by zoomingout when the user retreats back into the default “fly-through, frombird's eye view,” mode. Note that while such visual devices are veryeffective for delivering document highlights, they rely crucially onbeing able to carry out the layered analysis described with respect tocapsule overviews.

[0143] The RSVP Viewer is particularly well-suited for deployment in ascreen saver mode, in a background window on a desktop machine, or on alarge screen projection in communal areas. In any of these situations, atopic or context might catch a reader's peripheral attention, and thenthey can decide to take a further look. RSVP Viewer thus naturallyextends, and fits into, the emerging ‘push’ model of informationdelivery.

[0144] 8C. ViewTool Viewer

[0145] Referring now to FIGS. 8A-8C, what is shown is an embodiment ofthe ViewTool viewer. The ViewTool viewer freely borrows some of theideas of RSVP viewer. However, the emphasis here is to present a fulleroverview of the salient topic stamps in a document, one place, a single“overview” panel 804. This overview is contextualized to a document‘thumbnail’ 816, indicative of the distribution of these highly salientobjects in the text. At the same time, a separate ‘details’ area 806constantly displays additional information pertinent to the currentinformation-seeking context deployed by the user. The details area 806is used both for dynamic display of richer contexts, as in the RSVPviewer for providing access to the full text, or topically coherentsegments from it, on demand. Thus, the aim of this viewer is to developa more elaborate notion of context, while maintaining permanent focus onthe salient highlights (topic stamps) in the document. The ViewToolviewer further seeks to offer more interactivity to the user, in wayswhich make the targeted exploration of portions of the document naturaland transparent.

[0146] The ViewTool viewer places the capsule overview of a documentwithin the context of the document itself. This is maintained bysynchronized display of discourse segments, topic stamps, and relationalcontexts in three panels. The whole document 816 is displayed in theleft panel; this is deliberately unreadable, and is intended to functionas a document thumbnail serving as a contextual referent for the topicspresented in the central panel. With the use of an appropriate colorcoding scheme, it also serves as an indicator of the distribution oftopically prominent phrases in the document. The central panel 804 liststhe highly salient topic stamps. Contextualization for these is achievedby aligning the topic stamps for a given discourse segment with thetextual span of that segment in the thumbnail as indicated by 808 and810 in FIG. 8A and discussed below. This offers an immediate overviewof, for instance, what is being discussed in the beginning of thedocument, or in the end, or which topics keep recurring throughout, andso forth.

[0147] The central panel is sensitive to the user's focus of attention:as the mouse rolls over a topic stamp 804, the discourse segment fromwhich this topic has been extracted is highlighted in the left panelshown at 810. The highlighting also indicates the segmentation of thesource documents into topically different, and distinct, text sections.This design makes it easy to do rapid selection of areas of interest inthe document, as it is mediated by the topic stamps per segment display.Again, the granularity of analysis and the layered contextualinformation in the capsule overview make it easy to offer immediate andmore detailed information about any given set of topic stamps:simultaneously with highlighting the appropriate discourse segment 810in the left panel 802, relational contexts for the same set of topicstamps 808 and 812 are displayed cyclically, in RSVP-like fashion 814,in the right panel 806. This ensures that topic stamps are alwaysrelated with contextual cue phrases. Thus an additional level of detailis made available to the user, with very little ‘prompting’ on theirpart. On the other hand, as FIG. 8B illustrates, if it is still the casethat the full text of the segment would be required, clicking on its‘proxy’ topic stamps 808 (in the middle panel) would display this in theright panel 818. The larger area available there, as well as anautomatic readjustment of the size of type, ensures that the text isreadable.

[0148] Referring now to FIG. 8C, as a natural extension of the samemetaphor, clicking on the document proxy 816 in the left panel brings upthe full document text in the right panel 820. The full text always usescolor markup to indicate, in yet another way, topically salient phrasesand their relational contexts.

[0149] By always maintaining the larger document context for any grainof information of relevance and interest in the documents, ViewToolviewer is an ideal skimming tool, because it provides additionalinformation that may be important in deciding whether looking moreclosely at the document would be required. For example, users can get asense of the size of the document, whether it contains any pictures, andother visual cue features. They can see the density of topics and therelevant ordering of the topics in relation to the different sections ofthe document. The tool offers the ability to see arbitrarily detailedcontextual information relevant to a topic, while leveraging that samecontainment hierarchy of layered information units to prevent overload.

[0150] 8D. Viewer's Summary

[0151] The viewers in a preferred embodiment can be fully implemented inJava for cross-platform use, and can be deployed in a variety of wayswithin a suite of intranet tools for collaboration and communicationwithin communities. In one particular example of use, an on-linenewspaper has been configured as the primary news source within alearning community. By means of a variety of web spiders and documentfilters, external news stories are collected and ‘published’ in thenewspaper. RSVP is used for primary delivery of the external news, on adedicated page, projected on large display in a shared common area.TopicsTicker Viewer offers a brief overview of the latest news on thefront page of the newspaper. ViewTool Viewer is available as analternative browser, for more pro-active and focused access to thedocument particularly in situations where the newspaper is being viewedin personal workstations. ViewTool Viewer is also used for browsing ofpersonal information feeds, sent to a document analysis server enginevia a simple e-mail protocol. In general, any configuration of viewerscan be deployed for personalized ‘windows’ into continuous news feeds,combining a variety of screen delivery modes.

[0152] The notions of temporal typography and dynamic delivery ofcontent mediated via content highlights offer an appealing synergy ofform and content, which not only alleviates inevitable (given thecurrent state-of-the-art of text processing technology) shortcomings ofsummarization technologies today, but also suggests that additionalutility, and user satisfaction, can be derived from imperfect analysistechnologies—if usability and interface issues are addressed from thisperspective.

[0153] A system and method in accordance with the present invention isdisclosed which can present thematic capsule overviews of documents tousers. For each document a capsule overview is derived which will depictthe core content of an average length article in a more accurate andrepresentative manner than utilizing conventional techniques. Thecapsule overviews, delivered in a variety of dynamic presentation modes,allow the user to quickly get a sense of what a document is about, anddecide whether they want to read it in more detail. Thus, the system andmethod greatly facilitate the process of focused navigation into theparts of the document which may be of particular interest to the user.In a preferred embodiment the display of capsule overviews leveragenovel presentation metaphors for the dynamic delivery of content. Thisdelivery can be mediated by multilayered abstractions of documentcontent, making heavy use of ideas of temporal typography, in particularfor exploiting the interactions between form and content.

[0154] Although the present invention has been described in accordancewith the embodiments shown, one of ordinary skill in the art willreadily recognize that there could be variations to the embodiments andthose variations would be within the spirit and scope of the presentinvention. Accordingly, many modifications may be made by one ofordinary skill in the art without departing from the spirit and scope ofthe appended claims.

What is claimed is:
 1. A method for the dynamic presentation of thecontents of a plurality of documents on a display; comprising the stepsof: a) receiving a plurality of documents; b) providing a plurality ofcapsule overviews corresponding to the plurality of documents; and c)dynamically delivering document content as encapsulated within theplurality of capsule overviews.
 2. The method of claim 1 in which aplurality of capsule overviews include a containment hierarchy.
 3. Themethod of claim 2 in which the containment hierarchy ofinformation-bearing units provides different levels of abstractions ofthe document.
 4. The method of claim 3 in which the abstractionscomprise at least one topic stamp which is embedded within a pluralityof layers of progressively more informative text fragments related tothe document.
 5. The method of claim 2 wherein the at least one topicstamp is highly salient.
 6. The method of claim 2 in which thecontainment hierarchy is accessed automatically.
 7. The method of claim2 in which the containment hierarchy is accessed manually.
 8. The methodof claim 5 in which the document content is delivered via a TopicsTickerviewer.
 9. The method of claim 6 in which the document content isdelivered via a Rapid Serial Visual Presentation viewer.
 10. The methodof claim 6 in which the document content is delivered via a ViewToolviewer.
 11. The method of claim 7 in which the document content isdelivered via a Rapid Serial Visual Presentation viewer.
 12. The methodof claim 7 in which the document content is delivered via a ViewToolviewer.
 13. The method of claim 9 in which the Rapid Serial Presentationviewer comprises the cycling through a plurality of topic stamps andtheir associated relational contexts for the plurality of documents. 14.The method of claim 13 in which the cycling step comprises: a) selectinga document from the plurality of documents; b) selecting a topic stampfrom the document from the capsule overview; c) selecting a relationalcontext relating to the topic stamp from the capsule overview; d)retrieving a canonical form of the topic stamp from the capsuleoverview; e) displaying the topic stamp in background and the relationalcontext in the foreground for a time period that is calculatedautomatically; and f) repeating steps a-e for the plurality ofdocuments.
 15. The method of claim 14 in which the time period fordisplay is calculated based on amount of the relational context.
 16. Themethod of claim 15 wherein the topic stamp and relational context aredisplayed at different intensities.
 17. The method of claim 16 whereinthe topic stamp is dark and relational context is translucent.
 18. Themethod of claim 14 wherein the topic stamp and relational context zoomin and out.
 19. The method of claim 1 wherein the data is displayed viaa screen saver.
 20. The method of claim 1 wherein the data is displayedon a large screen projection.
 21. The method of claim 1 wherein the datais displayed in a background window on a computer.